opensteno_qmk/docs/feature_haptic_feedback.md

Haptic Feedback

Haptic feedback rules.mk options

The following options are currently available for haptic feedback in rules.mk:

HAPTIC_ENABLE = yes

HAPTIC_DRIVER += DRV2605L
HAPTIC_DRIVER += SOLENOID

The following config.h settings are available for all types of haptic feedback:

Settings	Default	Description
HAPTIC_ENABLE_PIN	Not defined	Configures a pin to enable a boost converter for some haptic solution, often used with solenoid drivers.
HAPTIC_ENABLE_PIN_ACTIVE_LOW	Not defined	If defined then the haptic enable pin is active-low.
HAPTIC_ENABLE_STATUS_LED	Not defined	Configures a pin to reflect the current enabled/disabled status of haptic feedback.
HAPTIC_ENABLE_STATUS_LED_ACTIVE_LOW	Not defined	If defined then the haptic status led will be active-low.
HAPTIC_OFF_IN_LOW_POWER	0	If set to 1, haptic feedback is disabled before the device is configured, and while the device is suspended.

Known Supported Hardware

Name	Description
LV061228B-L65-A	z-axis 2v LRA
Mini Motor Disc	small 2-5v ERM

Haptic Keycodes

Not all keycodes below will work depending on which haptic mechanism you have chosen.

Name	Description
HPT_ON	Turn haptic feedback on
HPT_OFF	Turn haptic feedback off
HPT_TOG	Toggle haptic feedback on/off
HPT_RST	Reset haptic feedback config to default
HPT_FBK	Toggle feedback to occur on keypress, release or both
HPT_BUZ	Toggle solenoid buzz on/off
HPT_MODI	Go to next DRV2605L waveform
HPT_MODD	Go to previous DRV2605L waveform
HPT_CONT	Toggle continuous haptic mode on/off
HPT_CONI	Increase DRV2605L continous haptic strength
HPT_COND	Decrease DRV2605L continous haptic strength
HPT_DWLI	Increase Solenoid dwell time
HPT_DWLD	Decrease Solenoid dwell time

Solenoids

First you will need a build a circuit to drive the solenoid through a mosfet as most MCU will not be able to provide the current needed to drive the coil in the solenoid.

Wiring diagram provided by Adafruit

Settings	Default	Description
SOLENOID_PIN	Not defined	Configures the pin that the Solenoid is connected to.
SOLENOID_PIN_ACTIVE_LOW	Not defined	If defined then the solenoid trigger pin is active low.
SOLENOID_DEFAULT_DWELL	12 ms	Configures the default dwell time for the solenoid.
SOLENOID_MIN_DWELL	4 ms	Sets the lower limit for the dwell.
SOLENOID_MAX_DWELL	100 ms	Sets the upper limit for the dwell.
SOLENOID_DWELL_STEP_SIZE	1 ms	The step size to use when HPT_DWL* keycodes are sent
SOLENOID_DEFAULT_BUZZ	0 (disabled)	On HPT_RST buzz is set "on" if this is "1"
SOLENOID_BUZZ_ACTUATED	SOLENOID_MIN_DWELL	Actuated-time when the solenoid is in buzz mode
SOLENOID_BUZZ_NONACTUATED	SOLENOID_MIN_DWELL	Non-Actuated-time when the solenoid is in buzz mode

• If solenoid buzz is off, then dwell time is how long the "plunger" stays activated. The dwell time changes how the solenoid sounds.
• If solenoid buzz is on, then dwell time sets the length of the buzz, while SOLENOID_BUZZ_ACTUATED and SOLENOID_BUZZ_NONACTUATED set the (non-)actuation times withing the buzz period.
• With the current implementation, for any of the above time settings, the precision of these settings may be affected by how fast the keyboard is able to scan the matrix. Therefore, if the keyboards scanning routine is slow, it may be preferable to set SOLENOID_DWELL_STEP_SIZE to a value slightly smaller than the time it takes to scan the keyboard.

Beware that some pins may be powered during bootloader (ie. A13 on the STM32F303 chip) and will result in the solenoid kept in the on state through the whole flashing process. This may overheat and damage the solenoid. If you find that the pin the solenoid is connected to is triggering the solenoid during bootloader/DFU, select another pin.

DRV2605L

DRV2605L is controlled over i2c protocol, and has to be connected to the SDA and SCL pins, these varies depending on the MCU in use.

Feedback motor setup

This driver supports 2 different feedback motors. Set the following in your config.h based on which motor you have selected.

ERM

Eccentric Rotating Mass vibration motors (ERM) is motor with a off-set weight attached so when drive signal is attached, the off-set weight spins and causes a sinusoidal wave that translate into vibrations.

#define FB_ERM_LRA 0
#define FB_BRAKEFACTOR 3 /* For 1x:0, 2x:1, 3x:2, 4x:3, 6x:4, 8x:5, 16x:6, Disable Braking:7 */
#define FB_LOOPGAIN 1 /* For  Low:0, Medium:1, High:2, Very High:3 */

/* Please refer to your datasheet for the optimal setting for your specific motor. */
#define RATED_VOLTAGE 3
#define V_PEAK 5

LRA

Linear resonant actuators (LRA, also know as a linear vibrator) works different from a ERM. A LRA has a weight and magnet suspended by springs and a voice coil. When the drive signal is applied, the weight would be vibrate on a single axis (side to side or up and down). Since the weight is attached to a spring, there is a resonance effect at a specific frequency. This frequency is where the LRA will operate the most efficiently. Refer to the motor's datasheet for the recommanded range for this frequency.

#define FB_ERM_LRA 1
#define FB_BRAKEFACTOR 3 /* For 1x:0, 2x:1, 3x:2, 4x:3, 6x:4, 8x:5, 16x:6, Disable Braking:7 */
#define FB_LOOPGAIN 1 /* For  Low:0, Medium:1, High:2, Very High:3 */

/* Please refer to your datasheet for the optimal setting for your specific motor. */
#define RATED_VOLTAGE 2
#define V_PEAK 2.8
#define V_RMS 2.0 
#define V_PEAK 2.1
#define F_LRA 205 /* resonance freq */

DRV2605L waveform library

DRV2605L comes with preloaded library of various waveform sequences that can be called and played. If writing a macro, these waveforms can be played using DRV_pulse(*sequence name or number*)

List of waveform sequences from the datasheet:

seq#	Sequence name	seq#	Sequence name	seq#	Sequence name
1	strong_click	43	lg_dblclick_med_60	85	transition_rampup_med_smooth2
2	strong_click_60	44	lg_dblsharp_tick	86	transition_rampup_short_smooth1
3	strong_click_30	45	lg_dblsharp_tick_80	87	transition_rampup_short_smooth2
4	sharp_click	46	lg_dblsharp_tick_60	88	transition_rampup_long_sharp1
5	sharp_click_60	47	buzz	89	transition_rampup_long_sharp2
6	sharp_click_30	48	buzz_80	90	transition_rampup_med_sharp1
7	soft_bump	49	buzz_60	91	transition_rampup_med_sharp2
8	soft_bump_60	50	buzz_40	92	transition_rampup_short_sharp1
9	soft_bump_30	51	buzz_20	93	transition_rampup_short_sharp2
10	dbl_click	52	pulsing_strong	94	transition_rampdown_long_smooth1_50
11	dbl_click_60	53	pulsing_strong_80	95	transition_rampdown_long_smooth2_50
12	trp_click	54	pulsing_medium	96	transition_rampdown_med_smooth1_50
13	soft_fuzz	55	pulsing_medium_80	97	transition_rampdown_med_smooth2_50
14	strong_buzz	56	pulsing_sharp	98	transition_rampdown_short_smooth1_50
15	alert_750ms	57	pulsing_sharp_80	99	transition_rampdown_short_smooth2_50
16	alert_1000ms	58	transition_click	100	transition_rampdown_long_sharp1_50
17	strong_click1	59	transition_click_80	101	transition_rampdown_long_sharp2_50
18	strong_click2_80	60	transition_click_60	102	transition_rampdown_med_sharp1_50
19	strong_click3_60	61	transition_click_40	103	transition_rampdown_med_sharp2_50
20	strong_click4_30	62	transition_click_20	104	transition_rampdown_short_sharp1_50
21	medium_click1	63	transition_click_10	105	transition_rampdown_short_sharp2_50
22	medium_click2_80	64	transition_hum	106	transition_rampup_long_smooth1_50
23	medium_click3_60	65	transition_hum_80	107	transition_rampup_long_smooth2_50
24	sharp_tick1	66	transition_hum_60	108	transition_rampup_med_smooth1_50
25	sharp_tick2_80	67	transition_hum_40	109	transition_rampup_med_smooth2_50
26	sharp_tick3_60	68	transition_hum_20	110	transition_rampup_short_smooth1_50
27	sh_dblclick_str	69	transition_hum_10	111	transition_rampup_short_smooth2_50
28	sh_dblclick_str_80	70	transition_rampdown_long_smooth1	112	transition_rampup_long_sharp1_50
29	sh_dblclick_str_60	71	transition_rampdown_long_smooth2	113	transition_rampup_long_sharp2_50
30	sh_dblclick_str_30	72	transition_rampdown_med_smooth1	114	transition_rampup_med_sharp1_50
31	sh_dblclick_med	73	transition_rampdown_med_smooth2	115	transition_rampup_med_sharp2_50
32	sh_dblclick_med_80	74	transition_rampdown_short_smooth1	116	transition_rampup_short_sharp1_50
33	sh_dblclick_med_60	75	transition_rampdown_short_smooth2	117	transition_rampup_short_sharp2_50
34	sh_dblsharp_tick	76	transition_rampdown_long_sharp1	118	long_buzz_for_programmatic_stopping
35	sh_dblsharp_tick_80	77	transition_rampdown_long_sharp2	119	smooth_hum1_50
36	sh_dblsharp_tick_60	78	transition_rampdown_med_sharp1	120	smooth_hum2_40
37	lg_dblclick_str	79	transition_rampdown_med_sharp2	121	smooth_hum3_30
38	lg_dblclick_str_80	80	transition_rampdown_short_sharp1	122	smooth_hum4_20
39	lg_dblclick_str_60	81	transition_rampdown_short_sharp2	123	smooth_hum5_10
40	lg_dblclick_str_30	82	transition_rampup_long_smooth1
41	lg_dblclick_med	83	transition_rampup_long_smooth2
42	lg_dblclick_med_80	84	transition_rampup_med_smooth1

Optional DRV2605L defines

#define DRV_GREETING *sequence name or number*

If haptic feedback is enabled, the keyboard will vibrate to a specific sqeuence during startup. That can be selected using the following define:

#define DRV_MODE_DEFAULT *sequence name or number*

This will set what sequence HPT_RST will set as the active mode. If not defined, mode will be set to 1 when HPT_RST is pressed.

DRV2605L Continuous Haptic Mode

This mode sets continuous haptic feedback with the option to increase or decrease strength.

Haptic Key Exclusion

The Haptic Exclusion is implemented as __attribute__((weak)) bool get_haptic_enabled_key(uint16_t keycode, keyrecord_t *record) in haptic.c. This allows a re-definition at the required level with the specific requirement / exclusion.

NO_HAPTIC_MOD

With the entry of #define NO_HAPTIC_MOD in config.h, the following keys will not trigger feedback:

• Usual modifier keys such as Control/Shift/Alt/Gui (For example KC_LCTL)
• MO() momentary keys. See also Layers.
• LM() momentary keys with mod active.
• LT() layer tap keys, when held to activate a layer. However when tapped, and the key is quickly released, and sends a keycode, haptic feedback is still triggered.
• TT() layer tap toggle keys, when held to activate a layer. However when tapped TAPPING_TOGGLE times to permanently toggle the layer, on the last tap haptic feedback is still triggered.
• MT() mod tap keys, when held to keep a usual modifier key pressed. However when tapped, and the key is quickly released, and sends a keycode, haptic feedback is still triggered. See also Mod-Tap.

NO_HAPTIC_FN

With the entry of #define NO_HAPTIC_FN in config.h, deprecated fn_actions type function keys will not trigger a feedback.

NO_HAPTIC_ALPHA

With the entry of #define NO_HAPTIC_ALPHA in config.h, none of the alpha keys (A ... Z) will trigger a feedback.

NO_HAPTIC_PUNCTUATION

With the entry of #define NO_HAPTIC_PUNCTUATION in config.h, none of the following keys will trigger a feedback: Enter, ESC, Backspace, Space, Minus, Equal, Left Bracket, Right Bracket, Backslash, Non-US Hash, Semicolon, Quote, Grave, Comma, Slash, Dot, Non-US Backslash.

NO_HAPTIC_LOCKKEYS

With the entry of #define NO_HAPTIC_LOCKKEYS in config.h, none of the following keys will trigger a feedback: Caps Lock, Scroll Lock, Num Lock.

NO_HAPTIC_NAV

With the entry of #define NO_HAPTIC_NAV in config.h, none of the following keys will trigger a feedback: Print Screen, Pause, Insert, Delete, Page Down, Page Up, Left Arrow, Up Arrow, Right Arrow, Down Arrow, End, Home.

NO_HAPTIC_NUMERIC

With the entry of #define NO_HAPTIC_NUMERIC in config.h, none of the following keys between 0 and 9 (KC_1 ... KC_0) will trigger a feedback.